Use HwLight.type as the key of mLightsByType

There are two paths to consider:
- HIDL HAL: We always set hwLight.id == hwLight.type == (byte)i;
- AIDL HAL: hwLight.id may be not equals to hwLight.type;
This patch use hwLight.type as the key of mLightsByType.

Change-Id: I5c8c4df4bb2d6bda44bdd62d2b9ac7d9cb674d3f
Signed-off-by: Tnze <cjd001113@outlook.com>